N.Y.C. Admin. Code § 450.43: Section 450.43

Section 450.43(A) – Revise Section 450.43(A) to read as follows:

(A) Type of Door. Each doorway leading into a vault from the building interior shall be provided with a tight-fitting door that has a minimum rating of 3 hours. Where practicable, basement vaults or vaults with an opening on a roof shall be provided with an outside entrance so that no entrance directly into the vault from the interior of the building will be necessary. Where entrance into the vault is from the interior of the building, the vault shall open into a vestibule, passage hall, or switchboard room not commonly in public use.

Exception: Where transformers are protected with an automatic sprinkler, water spray, carbon dioxide, or approved gas suppression system, construction of 1-hour rating shall be permitted.

Informational Note: For additional information, see NFPA 80-2016, Standard for Fire Doors and Other Opening Protectives.